Cool Tube Set Up and Review

How to choose your Cool Tube? Should you go for a Air Cooled Hood?

Hey there and welcome (back) to Free the Tree!
In this article we’re going to cover Cool Tubes and more precisely how to choose your own. We decided to make this review/guide since we bought our first one a little while ago and made a couple mistakes without knowing it.
Now that we’ve had enough time to look back and see our mistakes we wrote about them here so others can avoid making the same mistakes as us!

Cool Tube Review – Table of Content

What is a Cool Tube?

A Cool Tube is basically a glass tube with a light bulb connector within it. Both extremities are opened allowing you to place extracting tubes in them in order to connect the extractor and air filter if needed.

The main use for a Cool Tube is to contain the heat generated by the light bulbs within it, enabling the grower to extract it right away out of the grow room.

On average the temperature will drop about 2/3°C within the grow room. Another great advantage is that, with less heat generated by the light bulb, you’ll be able to get it much closer to the top of the plants, increasing light penetration while avoiding burning the tips of the buds.

Cooltube out of the box

CoolTube out of the box

Pros and Cons of a Cool Tube?

Installing a CoolTube definitely has its strong points, especially on the heat control level, but like anything it also comes at a cost.
In this section will bring to you all to positive and negative aspects of buying a cool tube, allowing you to make a educated decision.

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The Pro’s
  • Reduces the heat output generated from the light bulb.
  • You can get the light closer to the top of the plants
The Con’s
  • There is some light intensity loss since you’re adding a layer of glass between the bulb and the plant
  • Small loss in Lumens levels
  • If you don’t clean the cool tube at least in between each grow the loss in light intensity can be considerable.
  • Careful to chose a good reflector.
    If it’s not large enough you’ll have a coverage focused to the center of the room.

Different types of Cool tube reflectors

Within the Cool tube market you’ll basically find 2 families of Cool Tubes, the classic one that is accompanied by small reflector wings and the Air Cooled Hoods.
Let’s look at these two families closer:

The Original Cool Tube (the O.C)

The original cool tube is one the cheapest one out there and does the job.
As you can see in the images below, it is composed of a simple tube of glass, a reflector and the internal wiring for the light bulb. You’ll have to attach the wire to it before installing the Cool Tube into your room (here’s how).

Product image of cool tube with reflector wings attached

Air Cooled Tube with reflector wings

Extraction Tube and Electric Wire installed

Grow Room with a Basic Cool Tube installed

On our end we started with this one and the main disadvantage for our situation is the fact that the reflector wings are really small, and the coverage didn’t really cut it..
It was fine during the early vegetation when the plants were small and centered but once the grow room was covered the plants on the extremities didn’t get enough light.

Here’s a couple picture of this Cool Tube in Action, you’ll see that once the plants have nicely grown this small reflector just doesn’t cut it once the plants start reaching a certain size.

Early installation of tube, working fine with small plants

Small Plants – O.C light dispersion is sufficient


Leaves starting to go vertical, reaching for the light source

Intensity is not strong enough in those sections of the room

Air Cooled Hoods

Air Cooled Hoods are generally more expensive than your average CoolTube but are also a bit more advanced.
Instead of having a simple tube of glass you have a “box”. The bottom will be a sheet of glass, the top a much larger reflector and on each side 2 wholes allowing your to extract the hot air just like with the cool tube.

The main advantage with an Air Cooled Hood is light coverage given by the much larger reflector. The light intensity across the grow room will be much better and the plants will stop stretching and reaching for the light source.

Air cooled hood set up with electric wire

Air Cooled Hood our of the box

Cooling hood installed with a MH bulb running

Hood installed and running in grow room

Freshly installed Cooling Hood

As you can see the Hood’s larger reflector allows the light to be spread out much better across the room, meaning that the far corners of the room now have much stronger light intensity.

The difference within the plants was radical, they stopped stretching and reaching for the light source and grew much better from that point on.
Here’s a little comparison using the Cool Tube vs the Air Cooled Hood

Cool tube still in use, light penetration too low in the corners

Still using the Cool Tube – Corners of the room don’t have enough light

Larger reflectors allow the whole room to have much better light intensity

After installing Hood – Larger reflector give a better light coverage
(3 days after the previous pic)

I’m not sure you can see as huge of a difference that happened through these two images, but honestly it’s day and night coverage wise.
The larger reflector disperses the light at a much wider angle allowing the Cola’s that aren’t right under the light bulb to receive a sufficient amount of light. 🙂

Cool Tubes vs Air Cooled Hood

If you read the previous section than you might already see that our preference leans towards the cooled hood, mainly because of the fact that the Regular Cool Tube reflector just isn’t big enough for our room.

As we said, during the early vegetation stage and with smaller plants is was fine, but this time around our grow room is so full that it just doesn’t cut it any more.

Cool tube and Air Cooled Hood facing off

Air Cooled Hood vs Cool Tube set up

With our previous statements we’re not giving a fair view of the CoolTube because they do have strong advantages and definitely can do the deal. We finished our last grow with one and it worked fine and definitely did the job.
Let’s compare both quickly so you can have a global view of each.

Characteristics of Air Cooled Hoods vs Cool Tubes

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 Characteristics Cool Tube Air Cooled Hood
Cooled Air Flow Yes
Both sides are opened allowing you to attach extraction tubes on each end.
Both sides are opened allowing you to attach extraction tubes on each end.
Reflector Wings Generally Small.
On the basic version of the Cool Tube the reflector wings are very small (cf picture above)
The Cooling hood is large and the internal section facing down is fully composed of reflecting material.
Height and width Short and thin.
This is one of the mail advantages and/or disadvantages of the Cool Tube, it takes very little room within the grow room.
If you’re limited in space this might just be the way to go.
Wide and Deep.
To Cooled Hood is much wider and larger than a Cool Tube.
About 2/3 feet long and half that in width, you can’t have a mini grow room in order to use it.
MH/HPS compatibility Compatible with both light bulbs.
Personally we run them on 400W MH and HPS lights.
Same compatibility as the Cool Tube.
LED Compatibility No, and you don’t really need a cooltube is you’re running with LED’s since the heat generated is very low. I guess you could set something up.
The wiring isn’t prepared for a LED Set up but you do have the room, so if you fiddle around you probably could work something out.
Again, there’s little use since LEDs to generate much heat.
Main Advantage Smaller, cheaper and does the job. Wide coverage of light
Main Disadvantage Light Coverage isn’t very wide.
The light intensity in the corners of your grow room may not be sufficient.
The Air Cooled Hood takes quite a bit of room.
Whether in height or width you need to have sufficient room to set it up.

How to set up a Cool Tube or Air Cooled Hood?

Setting up your cool tube or Cooled Hood can be quite tricky, especially wiring it up.
We did a full tutorial on that over here so in this section we will cover the global steps but don’t hesitate to go check it our for the step by step process.

1. Wire up your Air Cooling System

Generally your Tube or Hood won’t come wired up which we found kind of crazy when un-boxing our first cool tube.
Wiring it up isn’t that complicated, no need to be an electrician or anything so don’t worry!

How to wire up your Cool Tube
Passing electric wires into cooltube

Wiring up Cool Tube or Cooled Hood

2. Visualize and Set Up the Tube or Hood

Before starting to place your cooling system within the grow room it’s important for you to visualize what’s going to go where. You don’t want to start moving everything around and realize that you don’t have enough room for extraction tubes, the light isn’t centered or any other mishaps that could occur.

While you visualize keep this set up order in mind:

  1. Air Filter (if you use one)
  2. Cool Tube or Cooled Hood
  3. Air extractor
  4. Room Exit
Order of air cooling system set up
How to wire up your Cool Tube

3. Place the Reflector on the Tube

You’re almost at the end of the road!
At this point you know where things are going to go, your cooling system’s is all wired up, all that’s missing is the reflector. Before doing these steps we recommend you to clean the glass of the tube or hood. You can use Windex or another glass cleaner, you want it to be as clean as possible.
After this, here’s what to do:

This step is only for Cool Tubes on Air Cooled Hoods the reflector is already set up.

  1. Remove the protective film on the Reflector. Ours was blue but the color can differ depending on the brand.
  2. Place the reflector on the top side of the tube.
    You can identify the top and bottom with the hooks that are to be used to secure the tube to the grow room.
  3. On some versions you can clip the reflector in place, others don’t have this clip. If you do you might as well use it to secure the reflector in place.

And voilà! The set up is finished and you’re ready to install it in your grow room!

Removing the protecting film on tube reflector

Preparing Reflector

4. Install the Tube or Hood in your room

Now that you’ve wired up the Cooling system, the reflector is attached and you’ve got an idea of where everything should go it’s time to get it in the room!
Here’s what you’ll want to do:

  1. Attach the line to the top of the grow room. Make sure it’s well secured, you don’t want it do drop on your plants
  2. Hook the line to the Cooled System. You’ll see that on each end a hook is there for this purpose.
  3. Get the plug out of the grow room and connect it to your ballast.
  4. Test it out!
    The first run you should definitely be around in case something goes wrong wiring wise, shouldn’t be the case if you followed our how-to but you never know.
String securing the cool tube to the top of the grow room

Attaching the Cooling System to Grow Room

Alright folks, That’s it for this one! Hopefully this helped you out in order to chose between a Cool Tube and Air Cooled Hoods, if not send us a message and we’ll try and get you some advice ASAP!
Until next time, be safe and grow easy!


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